Cylindrical nut and wrench

ABSTRACT

My invention relates to a new and improved type of cylindrical nut having an outer scalloped periphery and an improved wrench which has mating means including a pin to provide operative engagement with the cylindrical nut. The pin being located near the arcuate surface of the wrench, and having its center offset beyond the arcuate surface a distance proportional to the pin diameter in the order of one-sixth of the pin diameter to provide optimum design to all elements of the mating means.

United States Patent Franks 1 Feb. 15,1972

[54] CYLINDRICAL NUT AND WRENCH [72] Inventor: George W. Franks, 2619East Prince Road, Tucson, Ark. 85716 [22] Filed: June 30, 1969 [21 1Appl. No.: 837,462

52 U.S.Cl ..81/121B,s5/45 511 Int.Cl ..B25bl3/04 5s fieldofSearch..81/119,120,121;85/9,'45

[56] References Cited UNITED STATES PATENTS 1,285,899 11/1918 Barrett..81/119 2,079,056 4/1937 Warren ..85/9 X 3,482,481 12/1969 Newell etal. ..81/119 X Primary Examiner--Theron E. Condon AssistantExaminer-Eugene F. Desmond AttorneyEdward J. Cowan [57] ABSTRACT Myinvention relates to a new and improved type of cylindrical nut havingan outer scalloped periphery and an improved wrench which has matingmeans including a pin to provide operative engagement with thecylindrical nut. The pin being located near the arcuate surface of thewrench, and having its center offset beyond the arcuate surface adistance proportional to the pin diameter in the order of one-sixth ofthe pin diameter to provide optimum design to all elements of the matingmeans.

1 Claims, 7 Drawing Figures PATENTEDFEB15 m2 3,641,848

INVENTOR GEORGE W. FRAN w:

"' M Wg.Qura/n ATTORNEY CYLINDRICAL NUT AND WRENGH This inventionapplies to the transfer of torque from one mechanical member to anotherelement thru a cylindrical mated connection and specifically relates tothe combination of a simple type of cylindrical grooved surface or nutand an improved wrench therefor. The nut and wrench are both inexpensiveto manufacture and also provide the maximum amount of efficientoperation. The wrench has an inner radius substantially the same as theouter radius of the nut with a pin arranged to engage one or more of thegrooved surfaces of the cylindrical member or nut.

An object of this invention is to provide the torque transfer from amechanical member thru a pin to a driven element. This transfer oftorque passes thru a pin located in the wrench to the nut by acombination of shear and compressive stress against the pin.

Another object of this invention is the use of a cylindrical nut havingcylindrical grooves along its periphery to engage a cylindrical pin inthe wrench. The axis of the pin is parallel with that of the nut andlocated in the wrench such that part of its cylindrical surface projectsinto a groove of the nut.

Still another object of this invention is to reduce the manufacturingcost and yet provide an efficient and inexpensive nut which can be madeof cylindrical bar stock and will require a minimum amount of material.

A feature of this invention is the provision ofa simple openend wrenchof substantially the same radius as the cylindrical nut and containingone or more cylindrical pins located along its inside periphery toengage one or more grooves in the nut.

Another feature of this invention is the provision of a band whereextreme forces are applied to a nut when the cross-sectional areabetween the inner and outer diameters is relatively thin.

Still another feature of this invention is that the mating surfaces ofthe nut and wrench are so arranged that the wrench may be left inoperative engagement with the nut at alltimes.

The combined nut and wrench of this invention is an improvement over theprior art for the reason that square and hexagonal nuts require squareor hexagonal bar stock in their manufacture which is more expensive andrequires more material than the same size in cylindrical stock of whichnuts of this invention use in their manufacture.

The corners of both the square and hexagonal nuts tend to get roundedover with continued use, whereas with the nuts of this invention theouter surface is always in such a mated engagcment with the wrench thatit protects the grooves from this rounding over effect. Also the pin ofthe wrench is forced by this mated engagement to rotate into the grooveof the nut firmly and directly.

The wrench and nuts of this invention are also an improvement over theprior art type of spanner wrenches. One type being with a pin at one endthereof and an associated nut with holes in its outer diameter to engagethe pin of the wrench. In another type, the wrench has two pins arrangedto engage a pair of holes in the face of the nut. In such wrenches thepins of the spanner wrench will tend to bend and the holes of the nuttear out if excessive force is applied thereto. Whereas with the wrenchof this invention the pin or engaging member is in an axis parallel tothe axis of the nut and the grooved surfaces of the nut so that a muchgreater force can be applied to the driving member and transfered to thedriven element before shearing can take place in the pin of the wrenchor deformation ofthe outer surface of the nut.

This invention will best be understood by referring to the accompanyingdrawings in which FIG. I is a plan view of the nut ofthis invention.

FIG. 2 is an elevation of FIG. 1, part ofwhich is in section.

FIG. 3 is a plan view of the wrench, showing a cross section ofthehandle portion.

FIG. 4 is a sectional elevation ofa portion of FIG. 3.

FIG. 5 is a diagram showing a portion of the wrench and the forces whichare transfered thru the pin.

FIG. 6 is a plan view ofa wrench having three pins.

FIG. 7 is another plan view showing a modified wrench having a bandattached.

Referring now in detail to FIGS. 1 and 2, the cylindrical nut I which ismade of any type of durable material including metals, metal alloys, andplastics. The outer periphery of nut 1 has a plurality of cylindricalgrooves 2 which are uniformally spaced. The nut shown has eight groovesbut it is to be understood that one or any number of grooves may beused.

' The inner surface of the nut is threaded at 3 with any suitable threadform. The nut shown in the drawing, as an example. is one having a2-inch outer cylindrical diameter, His-inch internal thread with 8threads per inch, a thickness of inch, and Xe-inch diameter pin grooves.

In the practice of this invention, I propose establishing standard nutconfigurations. Each size would cover a specified internal thread rangeand would be grooved for a standard pin diameter proportional to that ofthe nut diameter. For example, a 2-inch diameter nut could have threadsfrom to 1%- inch diameter using any desired thread form and grooved fora %-inch diameter pin. Other standard nut diameters could be I 3, 4, 5,6, etc., inches having proportional internal thread ranges.

Referring now to FIGS. 3 and 4 the wrench 4 has an arcuate surface 5which extends approximately 30 beyond the center of nut I on both sides.The extension of this arcuate surface beyond the center insures a securemating of wrench 4 with nut I and permits the wrench to be left in anoperative engagement on the nut.

The central portion of the arcuate surface has located therein a pin 6which is driven into an aperture 7 in the body portion of the wrench 4and is positioned such as to extend beyond the arcuate portion 5 so asto engage a groove 2 in nut I. The thickness ofwrench 4 is similar tonut l.

The outer surface 8 of the wrench 4 extends from the ends 9 of thearcuate surface at an increasing sectional portion to a point 10 whereit forms the handle portion 11 which is of sufficient length to giveproper leverage and to provide a firm hold for the operator.

Referring now to FIG. 5, the diagram shows an example of how the sizeand position of the pin should be in order to give the maximum life toboth the wrench and the nut. One example of this would be for a %-inchdiameter pin for a 2-inch diameter nut with the pin axis located 1/16inch beyond the arcuate surface into the wrench, or the proportion ofone-sixth of the pin diameter. Torque applied to the wrench istransfered thru pin 6 to nut I. This is represented by a force F at anangle 0, drawn at 60, with respect to line L between center C of nut Iand the center of pin 6. It should be noted, that if the pin 6 is setfurther into the body of wrench 4 it will be held more securely. Yet atthe same time, this would cause angle 0 to become less and increaseforce F thereby decreasing the effectiveness of the wrench.

In the operation of this invention, applied torque T would cause wrench6 to rotate freely around nut 1 if pin 6 where missing. With pin 6 inplace, torque T is transferred from driving member 4 to driven element Ithru pin 6 by a combination of shear S and outward radial force R on pin6.

A major advantage of this invention over prior art is due to the unusualmanner in which the pin is positioned to resist shear force. Normally apin in a spanner wrench is placed such that it will resist shear acrossits cylindrical cross section. Whereas in this invention shear force Sis directed along surface 5 between elements I and 4 and is distributedacross the longitudinal cross section of pin 6. The advantage is thatfor a pin of a length equivalent to its diameter it has approximately1.273 times more longitudinal than circular area and this can beincreased by extending the pin. Therefore with this greater crosssection area possible, greater shear forces can be resisted with thesame pin.

The outward radial force R is caused by pin 6 being forced out of groove2 in nut 1 as torque T is applied to wrench 4. This force would be at aminimum for a pin which is half exposed and would increase as less ofthe pin is exposed to the nut. The force R would tend to compress pin 6into the driving member 4 and tighten the connection between theelements. This force is also distributed across the longitudinal area ofthe pin.

FIG. 6 shows a modified wrench 12 which has located in its arcuateinternal surface three pins l3. l4 and 15 which are arranged to engagetwo additional mated grooves in nut 1.

FIG. 7 shows another modified wrench having a band 16 secured by anysuitable means such as pins 17. The arcuate surface is provided with twopins 18 and 19. This type of wrench is optimum where the wall thicknessof the nut 1 is relatively thin and a maximum amount of torque is to beapplied to the nut 1 without deforming it. This wrench is also practicalin situations where access to a nut is limited.

Because all the shapes used in this nut and wrench combination are roundthey have a more natural resistance to wear than square and hexagonalnuts of which the corners tehd to be rounded through continued use.

This invention is especially adapted to relatively large diameter nutswhere the savings in material is much greater and the forces are alsomore extreme. Yet it would not be limited thereto as the same conditionsexist in small nuts such as A to inch diameter threads.

Although this invention has been described as a combination of acylindrical nut and a wrench therefor, it is to be understood that thetransfer of torque of this invention may be also applied to an externalcylindrical member having similar mating configurations.

Although this invention has been described as a wrench having a pin 6driven into body portion 7 and extending beyond the arcuate portion 5,it is to be understood that any type of mating means is within the scopeof this invention. In such mating means the pin could be substitutedwith a projection extending beyond the arcuate portion of the wrenchwhich could be formed by casting or forging in a one-piece construction.

I claim:

1. A wrench for a cylindrical nut having a plurality of parallel grooveslocated on its outer portion, said wrench having an arcuate portion anda handle portion, circular parallel mating means for said nut extendingbeyond the arcuate portion, the radius of the circular parallel matingmeans being equal to that of the groove of said nut and having its axislocated beyond the arcuate portion at a distance substantially equal toone-third the radius of said circular parallel mating means to providethe maximum strength to both nut and wrench, and having a band securedto the sides of said wrench to completely encircle the remaining portionof said nut which is not encircled by the arcuate portion of saidwrench.

1. A wrench for a cylindrical nut having a plurality of parallel grooveslocated on its outer portion, said wrench having an arcuate portion anda handle portion, circular parallel mating means for said nut extendingbeyond the arcuate portion, the radius of the circular parallel matingmeans being equal to that of the groove of said nut and having its axislocated beyond the arcuate portion at a distance substantially equal toone-third the radius of said circular parallel mating means to providethe maximum strength to both nut and wrench, and having a band securedto the sides of said wrench To completely encircle the remaining portionof said nut which is not encircled by the arcuate portion of saidwrench.